Fastener-driving tools, which may be pneumatically powered or combustion-powered, are used widely in building construction. Such pneumatically powered tools are exemplified in Golsch U.S. Pat. No. 4,932,480. Such combustion-powered tools are exemplified in Nikolich U.S. Pat. Re. 32,452 and in Nikolich U.S. patent application Ser. No. 07/848,277 filed Mar. 9, 1992.
Typically, such a pneumatically powered or combustion-powered tool includes a housing structure, a nosepiece extending from the housing structure, a primary actuating structure, and a secondary actuating structure. Both of these actuating structures are movably mounted upon the nosepiece. The primary actuating structure is movable between a tool-disabling position relative to the housing structure and a tool-enabling position relative thereto and is biased to the tool-disabling position. Typically, the fastener-driving tool also includes a trigger, which must be manually actuated to operate the tool once the tool has been enabled.
The primary actuating structure is arranged to enable the tool when such structure is moved to the tool-enabling position and to disable the tool when such structure is moved from the tool-enabling position. The secondary actuating structure is arranged to move the primary actuating structure to the tool-enabling position when the secondary actuating structure is pressed firmly against a workpiece.
For various applications, it is known to drive the fasteners to different depths of penetration so that their heads are flush with a workpiece, so that their heads remain disposed above the workpiece, or so that their heads are countersunk into the workpiece. Means known heretofore for adjusting the secondary actuating structure of such a tool so as to adjust the depths of penetration of fasteners driven by the tool into a workpiece have not been entirely satisfactory.